Journal of Volcanology and Geothermal Research最新文献

{"title":"Rapid emplacement of the Keaīwa Lava Flow of 1823 from the Great Crack in the Southwest Rift Zone of Kīlauea volcano","authors":"Andrea Tonato ,&nbsp;Thomas Shea ,&nbsp;Drew T. Downs ,&nbsp;Karim Kelfoun","doi":"10.1016/j.jvolgeores.2025.108391","DOIUrl":"10.1016/j.jvolgeores.2025.108391","url":null,"abstract":"<div><div>The Keaīwa Lava Flow of 1823 in the Southwest Rift Zone of Kīlauea volcano is unusual for its expansive pāhoehoe sheet flow morphology and lack of constructive vent topography, despite having a similar tholeiitic basalt composition to other lavas erupted from Kīlauea. This lava flow issued from a ∼10-km-long continuous fissure now known as the Great Crack, and has an unusually thin sheet flow morphology with margin thicknesses of ∼15–110 cm (average of 42 cm). Based on field observations of the lava flow at its fissure vent (e.g., drain-back features), we propose that the Great Crack formed, or at least significantly widened, just prior to and syn-eruptively with this 1823 eruption. The absence of pyroclastic cones or spatter ramparts indicates that the eruption consisted of a rapid outpouring of relatively degassed lava as the fissure unzipped. The rapidly moving lava flow overtopped pre-existing tumuli and scoria cones (e.g., Lava Plastered Cones) up to ∼10 m tall. Glass and whole-rock chemistry yield homogeneous compositions for the lavas erupted from the Great Crack, with glass compositions of 6.40 ± 0.10 wt% MgO and whole-rock compositions of 7.39 ± 0.07 wt% MgO. Lava pads erupted from a short western fissure system are richer in mafic minerals (e.g., olivine and clinopyroxene), and show slightly more MgO-rich whole-rock compositions (7.79 ± 0.05 wt%). MgO-in-glass thermometry on juvenile spatter yield eruption temperatures of 1153 ± 13°C that are typical of Kīlauea lavas. Thus, the extensive sheet-like lava flow morphology is not a direct consequence of unusual magmatic or rheological conditions (i.e., low viscosity). Instead, the flow morphology is associated with high effusion rates caused by sudden drainage of uprift magma as it erupted from the Great Crack. Lava flow modeling on a 2-m-resolution digital elevation model indicates that a minimum bulk effusion rate of ∼5800 m³/s (∼3500 m³/s dense rock equivalent) and a minimum flow velocity of ∼11 m/s are required for the lava flow to overcome the topography of the Lava Plastered Cones. This effusion rate is among the highest inferred for eruptions in Hawaiʻi and around the world. This study highlights a less frequent eruption style at Hawaiian volcanoes characterized by a sudden outpouring of lava from an unusual fissure system. Local eyewitness accounts indicate that the 1823 eruption was preceded by seismicity. Given the complex magmatic-volcanic-tectonic relations across Kīlauea, we speculate that the south flank could have slipped over one or more events that ultimately triggered unzipping of the Great Crack and passive release of briefly stored uprift magma. An eruption similar to 1823 at Kīlauea or Mauna Loa, with an eruptive timeframe that could be as short as an hour, with high effusion rates and rapid flow front velocities, would not easily allow for a timely response.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108391"},"PeriodicalIF":2.4,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CO2 flux and water geochemistry in Ribeira Quente river: A case study from a river draining an active central volcano (Furnas Volcano – São Miguel, Azores)","authors":"J. Virgílio Cruz ,&nbsp;César Andrade ,&nbsp;Letícia Ferreira ,&nbsp;Fátima Viveiros ,&nbsp;António Cordeiro ,&nbsp;Diogo Braga","doi":"10.1016/j.jvolgeores.2025.108398","DOIUrl":"10.1016/j.jvolgeores.2025.108398","url":null,"abstract":"<div><div>Building on previous studies that suggest that river water chemistry in Ribeira Quente watershed (Furnas Volcano) is influenced by hydrothermal discharges, measurements of the CO₂ fluxes along the major river and tributaries were made. The annual runoff in the river is estimated as 9.75 × 10⁶ m³ yr⁻¹, presenting a well-marked seasonal variation.</div><div>Waters are mainly of the Na-HCO₃ type, presenting a mean temperature of 19.53 ± 5.16 °C (median = 18.5 °C), reaching values as high as 38.5 °C, a mean EC equal to 325.24 ± 177.77 μS cm⁻¹ (median = 304.5 μS cm⁻¹), and are slightly acid to basic (mean pH = 7.07 ± 0.57; median = 7.1). Physico-chemical parameters and major-ion composition depict noticeable variations whenever hydrothermal discharges occur in the river channel. Besides mixing with hydrothermal discharges, water chemistry is also influenced by silicate weathering, processes also shown by the ¹³C/¹²C and ⁸⁷Sr/⁸⁶Sr isotopic ratios.</div><div>The total amount of CO₂ emitted along selected paths range between 20.5 t d⁻¹ and 23.8 t d⁻¹, values higher than the ones calculated dividing the river channel in separate sections (13 t d⁻¹–15.5 t d⁻¹), as the former values overestimates the area, thus leading to a higher overall flux calculation. CO₂ flux for all the watershed, estimated considering the contribution of all tributaries, is in the range of 14.6 t d⁻¹ to 17.7 t d⁻¹. Even if the CO₂ flux associated to surface water bodies in the study area is much lower than soil diffuse emissions, results point out to the need to characterize C-based GHG emissions from rivers draining active volcanic areas.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108398"},"PeriodicalIF":2.4,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stochastic ground motion simulation of earthquakes associated with September 19, 2021, Cumbre Vieja (La Palma Island) eruption: Determination of the quality factor Q, spectral decay parameter kappa, and site response","authors":"J. Rueda ,&nbsp;J. Mezcua","doi":"10.1016/j.jvolgeores.2025.108397","DOIUrl":"10.1016/j.jvolgeores.2025.108397","url":null,"abstract":"<div><div>The relatively strong damage caused by the seismicity associated with historical eruptions in La Palma (Canary Islands) makes it necessary to upgrade the seismic hazard of the island to produce seismic scenarios for future eruptions. Moreover, ancient earthquakes related to older eruptions can be studied if the seismic waves they produced are reproduced. To simulate such scenarios, the characteristics of the unknown earthquake must be determined: its focal characteristics including focal mechanism, location, magnitude, and stress drop; path properties, namely the geometrical spreading, quality factor Q, and its frequency dependence, along which the seismic waves propagate; and site effect. For the site effects, we considered the crustal and Vs30 amplification factors and the kappa value for the station, which represent the spectral amplitude diminution in the high-frequency band.</div><div>The simulation process used in this study is known as the stochastic simulation technique, which is based on the stochastic properties of strong ground motion and the utilization of a simple physical model for the source.</div><div>Considering the seismicity registered during the last eruption on the island of La Palma on September 19, 2021, we calculated the parameters required for the simulation to reproduce the strong ground motion of some of the recorded events. The adjustment of the observed to the recorded strong-motion records revealed the goodness of fit and the extent to which future simulations will be close to the real data.</div><div>The use of the calculated parameters in future studies would permit us to increase our knowledge of the seismic hazards on the island by considering different possible scenarios.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108397"},"PeriodicalIF":2.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144288803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of cristobalite and diktytaxitic textures on the physical properties of submarine rhyolite lavas from Havre volcano (Kermadec volcanic arc, Pacific Ocean)","authors":"Michael J. Heap ,&nbsp;Samuel J. Mitchell ,&nbsp;Rebecca J. Carey ,&nbsp;Alexandra R.L. Kushnir","doi":"10.1016/j.jvolgeores.2025.108392","DOIUrl":"10.1016/j.jvolgeores.2025.108392","url":null,"abstract":"<div><div>The <em>syn</em>-eruptive alteration of lavas can influence their physical, mechanical, and hydraulic properties, with implications for the outgassing of magmatic volatiles and the stability of volcanic structures. Although glass corrosion, resulting in porous diktytaxitic textures, and cristobalite precipitation is a common alteration type at both submarine and subaerial volcanoes, little is known as to their impact on rock properties. Here, therefore, we provide laboratory measurements of porosity, permeability, P-wave velocity, Young's modulus, and uniaxial compressive strength for a suite of rhyolitic lavas from the 2012 eruption at Havre volcano (Kermadec volcanic arc, Pacific Ocean; sampled in 2015) that have variable textures and contain variable quantities of cristobalite. We find that the cristobalite content of the lavas varies from 0 to ~26 area%, and that the cristobalite-rich (&gt; 10 area%) lavas are all associated with porous diktytaxitic textures. Lavas from the outermost, glassy carapace are cristobalite-poor, and lavas from the interior carapace are cristobalite-rich. Although porosity and permeability do not systematically increase with cristobalite content, the cristobalite-rich lavas from the interior carapace—those also associated with porous diktytaxitic textures—are consistently porous (&gt; ~0.13) and permeable (&gt; ~10⁻¹⁵ m²) and contain essentially no isolated porosity, which can reach up to 0.1 in the cristobalite-poor lavas from the outermost, glassy carapace. The presence of porous diktytaxitic textures in the cristobalite-rich lavas appears to lower P-wave velocity, but does not appear to reduce Young's modulus or uniaxial compressive strength. The presence of commonly-observed macrofractures in lavas from the outermost, glassy carapace increases their permeability and lowers their strength. We discuss the implications of these laboratory data for fluid movement and outgassing in, and the structure—in terms of rock physical, mechanical, and hydraulic properties—and stability of, submarine lava domes.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108392"},"PeriodicalIF":2.4,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling recurrent Pleistocene-Holocene multiphase explosive eruptions of Pico de Orizaba (Citlaltépetl), Mexico, from lithostratigraphic analysis and radiocarbon dating","authors":"Matías Vásquez-Montoya ,&nbsp;Rafael Torres-Orozco ,&nbsp;José Luis Arce ,&nbsp;Katrin Sieron ,&nbsp;Francisco Córdoba-Montiel","doi":"10.1016/j.jvolgeores.2025.108384","DOIUrl":"10.1016/j.jvolgeores.2025.108384","url":null,"abstract":"<div><div>The complex explosive eruptive history of the andesitic-dacitic Pico de Orizaba (Citlaltépetl) – the tallest stratovolcano in North America (5636 masl) – has been investigated through detailed lithostratigraphic analysis and radiocarbon dating of Pleistocene-Holocene deposits. The study documents 40 bedsets, each composed of multiple layers representing either fall (36 bedsets) or pyroclastic density current (PDC) deposits (23 bedsets). Correlation of these bedsets across 86 study sites encompassing the entire volcanic edifice has refined Pico de Orizaba's stratigraphic framework. Radiocarbon dating of key deposits reveals Holocene eruptive pauses of 100–800 years and allows for a reappraisal of the eruptive history and chronology of the Lower (8.6–8.4 ka) and Upper Citlaltépetl (8.3–8.2 ka) episodes. Lithostratigraphic and lithofacies analysis suggests that 10 Pleistocene and 12 Holocene bedsets were formed during multiphase explosive eruptive episodes. These episodes span variable sequences of eruptive phases, from onset dome collapse (block-and-ash flows) and conduit-clearing outbursts to climactic eruption columns and waning column collapse PDCs. Field evidence indicates a significantly higher frequency of explosive eruptions than previously documented. These findings enhance our understanding of Pico de Orizaba's episodic explosive behavior and have critical implications for volcanic hazard assessment in the surrounding densely populated regions. The study also emphasizes the value of integrating detailed stratigraphic data to reconstruct eruptive histories and incorporate multiphase eruptive activity into hazard models.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108384"},"PeriodicalIF":2.4,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origins and fluxes of gas emissions from the Central Volcanic Zone of the Andes","authors":"J. Maarten de Moor ,&nbsp;Peter H. Barry ,&nbsp;Alejandro Rodríguez ,&nbsp;Felipe Aguilera ,&nbsp;Mauricio Aguilera ,&nbsp;Cristóbal Gonzalez ,&nbsp;Susana Layana ,&nbsp;Agostina Chiodi ,&nbsp;Fredy Apaza ,&nbsp;Pablo Masias ,&nbsp;Christoph Kern ,&nbsp;Jaime D. Barnes ,&nbsp;Jeffrey T. Cullen ,&nbsp;Deborah Bastoni ,&nbsp;Alessia Bastianoni ,&nbsp;Martina Cascone ,&nbsp;Christofer Jimenez ,&nbsp;Jessica Salas-Navarro ,&nbsp;Carlos Ramírez ,&nbsp;Gerdhard L. Jessen ,&nbsp;Karen G. Lloyd","doi":"10.1016/j.jvolgeores.2025.108382","DOIUrl":"10.1016/j.jvolgeores.2025.108382","url":null,"abstract":"<div><div>We present geochemical data from gas samples from ∼1200 km of arc in the Central Volcanic Zone of the Andes (CVZA), the volcanic arc with the thickest (∼70 km) continental crust globally. The primary goals of this study are to characterize and understand how magmatic gases interact with hydrothermal systems, assess the origins of the major gas species, and constrain gas emission rates. To this end, we use gas chemistry, isotope compositions of H, O, He, C, and S, and SO₂ fluxes from the CVZA. Gas and isotope ratios (CO₂/S_T, CO₂/CH₄, H₂O/S_T, δ¹³C, δ³⁴S, ³He/⁴He) vary dramatically as magmatic gases are progressively affected by hydrothermal processes, reflecting removal and crustal sequestration of reactive species (e.g., S) and addition of less reactive meteoric and crustal components (e.g., He). The observed variations are similar in magnitude to those expected during the magmatic reactivation of volcanoes with hydrothermal systems. Carbon and sulfur isotope compositions of the highest temperature emissions (97–408 °C) are typical of arc magmatic gases. Helium isotope compositions reach values similar to upper mantle in some volcanic gases indicating that transcustal magma systems are effective conduits for volatiles, even through very thick continental crust. However, He isotopes are highly sensitive to even low degrees of hydrothermal interaction and radiogenic overprinting. Previous work has significantly underestimated volatile fluxes from the CVZA; however, emission rates from this study also appear to be lower than typical arcs, which may be related to crustal thickness.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108382"},"PeriodicalIF":2.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of the hydrothermal system of Hakone volcano","authors":"Nobuo Matsushima ,&nbsp;Kazutaka Mannen","doi":"10.1016/j.jvolgeores.2025.108383","DOIUrl":"10.1016/j.jvolgeores.2025.108383","url":null,"abstract":"<div><div>The eruption of fumarolic gases and hot springs from active volcanoes indicates the existence of magmatic hydrothermal systems. Numerical simulations were performed to reproduce the surface manifestations at Hakone volcano. At this site, high-chloride hot springs are concentrated at the northeastern foot of the central cone. The simulation indicates that this distribution of hot springs can be explained by topographic effects. When supercritical water containing NaCl rises from depth beneath the central cone, vapor–liquid separation occurs near sea level, and the NaCl-rich liquid phase flows laterally because of the influence of the topography and discharges from hot springs. Meanwhile, the vapor phase continues to rise, forming a vapor-dominated hydrothermal system beneath the central cone, which leads to fumarolic activity at the summit area. This relatively simple model can reproduce the hydrothermal system of Hakone volcano, but only if we consider topography. By comparison between observation and numerical simulations, we estimated the rate and location of supercritical water upflow. This upflow location corresponds with the source area of crustal deformation observed immediately before the 2015 eruption. We suggest that a disturbance in this flow system may have triggered the eruption.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108383"},"PeriodicalIF":2.4,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A transparent IHPV for the in-situ geochemical characterization of magmatic volatile phases and melts","authors":"Marion Louvel ,&nbsp;Denis Testemale ,&nbsp;Alain Prat ,&nbsp;Eric Lahera ,&nbsp;William Del-Net ,&nbsp;Aneta Slodczyk ,&nbsp;Benjamin Langerome ,&nbsp;Remi Champallier ,&nbsp;Richard Brooker ,&nbsp;Anita Cadoux ,&nbsp;Jasper Berndt ,&nbsp;Jean-Louis Hazemann","doi":"10.1016/j.jvolgeores.2025.108381","DOIUrl":"10.1016/j.jvolgeores.2025.108381","url":null,"abstract":"<div><div>Chemical exchanges between magmas and volatile-rich fluids and gases are fundamental processes of magmatic and volcanic activity, but also play a critical role in the formation of various ore deposits. Yet, the composition and properties of the so-called magmatic volatile phases (MVPs) remain elusive, due to difficulties in their sampling, both in natural systems and in experimental laboratories.</div><div>Here, we present a novel ‘transparent’ internally-heated high-pressure vessel (T-IHPV) that enables the geochemical characterization of coexisting hydrous melts and MVPs in-situ, under typical shallow magmatic conditions. The experimental design is validated through the observation of haplogranite and rhyodacite melting to 900 °C and 130 MPa and the in-situ X-ray absorption (XAS) study of bromine and strontium distribution and speciation in the haplogranite-H₂O system to 800 °C and 100 MPa. These preliminary experiments confirm the efficient partitioning of Br in MVPs in differentiated systems (<span><math><msubsup><mi>D</mi><mi>Br</mi><mrow><mi>MVP</mi><mo>/</mo><mi>melt</mi></mrow></msubsup></math></span> around 41 for haplogranite) and reveal the stability of hydrated Br species instead of HBr in the MVPs. Coupled to other spectroscopic methods (Raman, SAXS/WAXS, XRD), we expect the T-IHPV to shed a new light on the thermodynamics and kinetics of chemical reactions at stake in shallow magmatic and hydrothermal reservoirs.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"466 ","pages":"Article 108381"},"PeriodicalIF":2.4,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revealing the shear-wave velocity structure of Tangkuban Parahu Volcano, West Java, Indonesia using Ambient Noise Tomography","authors":"Aditya Lesmana ,&nbsp;Awali Priyono ,&nbsp;Andri D. Nugraha ,&nbsp;Zulfakriza ,&nbsp;Shindy Rosalia ,&nbsp;David P. Sahara ,&nbsp;Rexha Verdhora Ry ,&nbsp;Sri Widiyantoro ,&nbsp;Wahyu Hidayat ,&nbsp;Faiz Muttaqy ,&nbsp;Devy Kamil Syahbana ,&nbsp;Ahmad Basuki ,&nbsp;Kristianto","doi":"10.1016/j.jvolgeores.2025.108371","DOIUrl":"10.1016/j.jvolgeores.2025.108371","url":null,"abstract":"<div><div>We present a shear-velocity model for the Tangkuban Parahu Volcano (TPV) using ambient seismic noise tomography. We used data from a three-month 55-temporary netwok deployed between October 2021 and February 2022. We cross-correlated the vertical components at each station to extract an empirical Green's function, to generate group velocity maps within the periodicity range of 1 to 6.5 s. We then construct a three-dimensional model of shear-wave velocity to a depth of 5 km below the summit. Our analysis revealed distinct patterns of high and low velocity values, associated with the presence of the old Sunda caldera, unmapped local structures, and surface geothermal manifestation around TPV. We identified low velocity zones indicative of shallow reservoirs and pathways for magma migration from the subsurface to surface crater. Additionally, high velocity zones observed, correspond to cooled magmatic bodies.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108371"},"PeriodicalIF":2.4,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life and death of a sinter archive: Evolution of siliceous hot-spring deposits (Holocene) on the dynamic Paeroa Fault at Te Kopia, Taupō Volcanic Zone, New Zealand","authors":"M.C. Rowe ,&nbsp;K.A. Campbell ,&nbsp;A. Hamilton ,&nbsp;Y. Jiang ,&nbsp;J. Pelser ,&nbsp;B. Murphy ,&nbsp;R. Martin ,&nbsp;K.M. Mackenzie ,&nbsp;D.A. Stallard ,&nbsp;B. Lyon ,&nbsp;A. Langendam ,&nbsp;E.E. Nersezova ,&nbsp;D.M. Guido ,&nbsp;J.V. Rowland","doi":"10.1016/j.jvolgeores.2025.108380","DOIUrl":"10.1016/j.jvolgeores.2025.108380","url":null,"abstract":"<div><div>Siliceous hot spring deposits, or sinter, host a variety of extremophile microorganisms in modern geothermal settings, and are often touted as an important candidate in the search for early life on Earth or elsewhere in the solar system. However, the preservation potential of microbial textures within silica may be compromised over geologic time scales, particularly in active tectonic and/or volcanic environments. The Te Kopia geothermal field, Taupō Volcanic Zone (TVZ), New Zealand, situated along the dramatic Paeroa Fault (with up to 500 m offset, and demarcating the eastern boundary of the central TVZ), provides a natural laboratory to investigate the preservation state of microbial textures/microfossils in young (&lt;5140 years BP) siliceous sinter that was originally deposited from circum-neutral alkali-chloride geothermal fluids (∼100 °C to ambient) discharging at the land surface. Since its formation, various processes – mechanical (landslides), biological (vegetation), chemical (acidic leaching) – have rapidly degraded the relict sinter. Combined field mapping and petrographic observations of sinter textures indicate a prolonged history of alkali-chloride fluid surface discharge, with multiple stages of fluid flow and changing flow directions over an expansive area, prior to a shift to acid-sulfate thermal fluid chemistry associated with a drop in the local water table, possibly related to fault activity. Mineralogy (X-ray diffraction) and in situ geochemistry (electron microprobe analysis, synchrotron X-ray fluorescence) illustrate the effects of acidic hydrothermal alteration, with accelerated recrystallization of opal-A to opal-CT and quartz, and the leaching and overprinting of geochemical tracers of sinter growth and microbial textures (e.g., Rb, Ga, Al, Fe). Results suggest that despite the proportionally minor amount of vent geyserite sinter compared to low-temperature palisade sinter in the study area, the dense nature of spring vent-related geyserite enhances its preservation potential compared to the more porous, filamentous microbial textures of the distal sinter apron-related palisade texture.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108380"},"PeriodicalIF":2.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}